<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        *{margin:0;padding: 0px;}
    .nav{
        width:1000px;
        margin: 0 auto;
        background: rgb(88, 88, 88);
        
    }
    .drop-down{
        position: relative;
    }
    .drop-menu{
        background: #000;
        position: absolute;
        display:none;
        width:100px;
    }
    .row::after{
        content:"";
        display:table;
        clear:both;
    }
    ul{
        line-height: 50px;
        list-style:none;
    }
    a{
        text-decoration: none;
        color:#fff;
    }
    .drop-menu a{
        
        display:block;    
        
    }
    .drop-down:hover .drop-menu{
        display:block;
    }
     li{
        text-align: center;
        float:left;
        width:100px;
    }
    </style>
</head>
<body>
    <ul class="nav row">
        <li class="drop-down">
            <a href="#">收藏夹</a>
            <div class="drop-menu">
                <a href="#">1</a>
                <a href="#">2</a>
            </div>
        </li>
        <li><a href="#">卖家</a></li>
        <li><a href="#">买家</a></li>
    </ul>
    
</body>
</html>